Load the map leavenworth. If you don't how to do this then bring up the console with ~ or tab and type : Map leavenworth

now enter the the following cheat into the console: mpcheat ghost

now due right and against the wall of where you start is cell which is mysteriously full of water.

In this cell is a shark swimming around with laser beam on it's head.

I personally believe it a refrence to Austin Powers.